The block provides a recommended experiment length in the Experiment Length section
of the block parameters. Typically, you configure the start/stop signal such that there is at
least that much time between the rising and falling signals. You must also make sure that
the simulation does not stop before the experiment stops. For more information about
how the block determines the recommended experiment length, see the Frequency
Response Estimator block reference page.
Step 3. Set Experiment Parameters
The frequency-response estimation experiment injects sinusoidal signals at the
frequencies you specify with the Frequencies parameter (or at the w port) of the
Frequency Response Estimation block. Specify the perturbation amplitudes using the
Amplitudes parameter (or at the amp port.
The block can apply the perturbation at each frequency separately (sinestream mode) or
simultaneously (superposition mode). To specify which mode to use, set the Experiment
mode parameter.
- Sinestream mode — Applies the perturbation one frequency at a time. Sinestream
mode can be more accurate and can accommodate a wider range of frequencies than
superposition mode. - Superposition — Applies the perturbation as a superposition signal containing all
frequencies at once. The estimation experiment is generally faster in superposition
mode.
You can also specify parameters that tell the block how to long to let the system settle
when the perturbation is applied, and how long to measure the response for the
estimation. For further details about the two signal types and their relative advantages,
see the Experiment mode parameter description on the Frequency Response Estimator
block reference page.
Step 4. Run Model and Examine Estimated Frequency
Response
After you have configured all the parameters for the estimation experiment, run the
model. Allow the model to run long enough to complete the estimation experiment, based
on the recommended experiment length provided by the block. If you select Display
Bode plot, the block generates a Bode plot to visualize the estimated frequency response
during the experiment.
Online Estimation Using Plant Modeled in Simulink